- ID:
- ivo://CDS.VizieR/J/A+A/467/73
- Title:
- 3{sigma} hard sample of XMDS survey
- Short Name:
- J/A+A/467/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our goal is to probe the populations of obscured and unobscured AGN investigating their optical-IR and X-ray properties as a function of X-ray flux, luminosity and redshift within a hard X-ray selected sample with wide multiwavelength coverage. We selected a sample of 136 X-ray sources detected at a significance of >=3{sigma} in the 2-10keV band (F_2-10_>~10^-14^erg/cm^2^/s) in a ~1deg^2^ area in the XMM Medium Deep Survey (XMDS, Cat. <J/A+A/439/413>). The XMDS area is covered with optical photometry from the VVDS and CFHTLS surveys and infrared Spitzer data from the SWIRE survey. Based on the X-ray luminosity and X-ray to optical ratio, 132 sources are likely AGN, of which 122 have unambiguous optical - IR identification. The observed optical and IR spectral energy distributions of all identified sources are fitted with AGN/galaxy templates in order to classify them and compute photometric redshifts. X-ray spectral analysis is performed individually for sources with a sufficient number of counts and using a stacking technique for subsamples of sources at different flux levels. Hardness ratios are used to estimate X-ray absorption in individual weak sources.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/426/97
- Title:
- SIMBA survey. 1.2-mm/IRAS sources
- Short Name:
- J/A+A/426/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a 1.2mm continuum emission survey toward 146 IRAS sources thought to harbour high-mass star forming regions. The sources have FIR colors typical of UCHII regions and were detected in the CS (2-1) line survey of Bronfman et al. (1996, Cat. J/A+AS/115/81). Regions of 15'x10', centered on each IRAS source, were mapped with an angular resolution of ~24", using the SIMBA array on the SEST telescope. 1.2mm emission was detected toward all IRAS sources. We find that the dust cores associated with these sources have typical sizes of 0.4pc and masses of 5x10^3^M_{sun}. Dust temperatures and luminosities, derived from the SED, are typically 32K and 2.3x10^5^L_{sun}_.
- ID:
- ivo://CDS.VizieR/J/A+A/543/A61
- Title:
- SINFONI data cube of NGC 7552
- Short Name:
- J/A+A/543/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Approximately 20% of all spiral galaxies display starburst activity in nuclear rings of a few hundred parsecs in diameter. It is our main aim to investigate how the starburst ignites and propagates within the ring, leading to the formation of massive stellar clusters. We observed the ring galaxy NGC 7552 with the mid-infrared (MIR) instrument VISIR at an angular resolution of 0.3"-0.4" and with the near-infrared (NIR) integral-field spectrograph SINFONI on the VLT, and complement these observations with data from ISO and Spitzer. The starburst ring is clearly detected at MIR wavelengths at the location of the dust-extincted, dark ring seen in HST observations. This "ring", however, is a rather complex annular region of more than 100 parsec width. We find a large fraction of diffuse [NeII] and PAH emission in the central region that is not associated with the MIR peaks on spatial scales of ~30pc. We do not detect MIR emission from the nucleus of NGC 7552, which is very prominent at optical and NIR continuum wavelengths. However, we have identified nine unresolved MIR peaks within the ring. The average extinction of these peaks is A_V_=7.4 and their total infrared luminosity is L_IR_=2.1x10^10^L_{sun}_. The properties of these peaks are typical for MIR-selected massive clusters found in other galaxies. The ages of the MIR-selected clusters are in the range of 5.9+/-0.3Myr. The age spread among the clusters of 0.8Myr is small compared to the travel time of ~5.6Myr for half an orbit within the starburst ring. We find no strong evidence for a scenario where the continuous inflow of gas leads to the ongoing formation of massive clusters at the contact points between galactic bar and starburst ring. Instead, it appears more likely that the gas density build up more gradually over larger ring segments, and that the local physical conditions govern cluster formation. We note that the fundamental limitation on the accurate derivation of cluster age, mass and initial mass function slope is the lack of higher angular resolution. Resolving the highly embedded, massive clusters requires milli-arcsecond resolution at infrared wavelengths, which will be provided by the next generation of instruments on extremely large telescopes (ELTs).
- ID:
- ivo://CDS.VizieR/J/A+A/552/L2
- Title:
- SINFONI K-band observations of IRS54(YLW52)
- Short Name:
- J/A+A/552/L2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Molecular outflows from very low-mass stars (VLMSs) and brown dwarfs have been studied very little. So far, only a few CO outflows have been observed, allowing us to map the immediate circumstellar environment. We present the first spatially resolved H_2_ emission around IRS54 (YLW52), a ~0.1-0.2M_{sun}_ Class I source. By means of VLT SINFONI K-band observations, we probed the H2 emission down to the first ~50AU from the source. The molecular emission shows a complex structure delineating a large outflow cavity and an asymmetric molecular jet. Thanks to the detection of several H_2_transitions, we are able to estimate average values along the jet-like structure (from source position to knot D) of Av~28mag, T~2000-3000K, and H_2_column density N(H_2)~1.7x10^17cm^-2. This allows us to estimate a mass loss rate of ~2x10^-10M_{sun}_/yr for the warm H_2_component . In addition, from the total flux of the Br gamma line, we infer an accretion luminosity and mass accretion rate of 0.64L_{sun}_ and ~3x10^-7M_{sun}_/yr, respectively. The outflow structure is similar to those found in low-mass Class I and CTTS. However, the Lacc/Lbol ratio is very high (~80%), and the mass accretion rate is about one order of magnitude higher when compared to objects of roughly the same mass, pointing to the young nature of the investigated source.
- ID:
- ivo://CDS.VizieR/J/A+A/557/A94
- Title:
- SiO and HCO+ massive molecular outflows
- Short Name:
- J/A+A/557/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a study of 14 molecular outflows associated with high-mass star formation. We used the IRAM30m telescope to characterize the outflow emission in the SiO(2-1), SiO(5-4) and HCO^+^(1-0) lines. We detect outflows in all the 14 high-mass star-forming regions in both, the SiO and HCO^+^ lines. Six of the fourteen outflows show bipolarity. The physical parameters derived for these outflows are consistent with outflows powered by massive young stellar objects with luminosities in the range 10^3^-10^4^L_{sun}_. We found a decrease of the SiO abundance (from 10^-8^ to 10^-9^) as the object evolves in time, while there are hints of a possible increase of the HCO^+^ outflow energetics with time. These results suggest a scenario in which SiO is largely enhanced in the first evolutionary stages, probably due to strong shocks produced by the protostellar jet. As the object evolves, the power of the jet would decrease and so does the SiO abundance. During this process, however, the material surrounding the protostar would have been swept up by the jet, and the outflow activity, traced by entrained molecular material (HCO^+^), would increase with time.
- ID:
- ivo://CDS.VizieR/J/PASJ/59/559
- Title:
- SiO maser search off the Galactic plane
- Short Name:
- J/PASJ/59/559
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We searched for the SiO J=1-0, v=1 and 2 maser lines at ~43GHz in 277 2MASS/MSX/IRAS sources off the Galactic plane (|b|>~3{deg}), which resulted in 119 (112 new) detections. Among the new detections, two are very faint objects with MSX 12{mu}m flux densities below 2Jy. These are likely to be O-rich AGB-stars associated with dwarf-galaxy tidal tails. The sample also includes medium bright MSX objects at moderately high galactic latitudes (3{deg}<|b|<5{deg}) and in the IRAS gap at higher latitudes. A signature of a warp of the inner Galactic disk is found for a disk subsample. This warp appears relatively strongly in the area of 0{deg}<l<45{deg} and 3{deg}<|b|<5{deg}. We also found a group of stars that does not follow to the Galactic rotation. This feature appears in the Galactic disk at l~27{deg}, and extends more than 15{deg} in the galactic latitude, like a stream of tidal debris from a dwarf galaxy.
957. SiO maser sources
- ID:
- ivo://CDS.VizieR/J/ApJS/106/463
- Title:
- SiO maser sources
- Short Name:
- J/ApJS/106/463
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observations in the 28SiO J=1-0 v=1, J=1-0 v=2 lines and the 29SiO J=1-0, v=0 lines were simultaneously made toward 181 color-selected IRAS sources in the outer disk of the Galaxy (at longitudes between 90 deg and 250 deg). The 28SiO lines were detected in 63 sources (56 new) and the 29SiO line in 11 sources (9 new). Most of the detections are optically variable stars, mainly Mira-type variables and a few semiregular variables. The detection rate (35%) is much lower than that of the bulge survey performed by the same observational system - the 45m telescope at Nobeyama Radio Observatory. The lower detection rate of SiO maser emission is partly attributed to the increase of contaminations by stars with C-rich circumstellar envelopes and young stellar objects in the outer disk sample. The kinematical implications of the observational results are also discussed. The luminosity distances to the SiO maser sources are estimated from their IRAS fluxes at 12um and colors. By combining the SiO radial velocity and the luminosity distance, the rotation curve of the outer Galactic disk is found to be slightly falling within the Galactocentric distance between 8.5 and 12kpc. The sources located within 20deg from the Galactic anticenter direction are used to check for a peculiar motion of the local standard of rest.
- ID:
- ivo://CDS.VizieR/J/PASJ/58/529
- Title:
- SiO Maser Survey in Galactic Bulge
- Short Name:
- J/PASJ/58/529
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We surveyed 291 MSX/2MASS infrared objects in the 7{deg}x2{deg} area of the galactic center in the 43GHz SiO J=1-0 v=1 and 2 maser lines, obtaining accurate radial velocities of 163 detected objects. The surveyed area is the region where the IRAS catalog is incomplete due to contamination by high source density. The objects in the present MSX/2MASS sample were chosen to have similar infrared characteristics to those of the previous SiO-maser-survey samples based on the color-selected IRAS sources. The sampling based on the 2MASS catalog causes a bias to the foreside objects of the bulge due to heavy obscuration by interstellar dust; the detections considerably leaned on the V_lsr_<0 side.
- ID:
- ivo://CDS.VizieR/J/PASJ/55/229
- Title:
- SiO maser survey of cold IRAS sources
- Short Name:
- J/PASJ/55/229
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of observations of cold IRAS sources in the Galactic disk area, -10{deg}<l<100{deg} and |b|<5{deg}, in the SiO J=1-0, v=1 and 2 maser lines. SiO masers were detected in 51 out of 143 observed sources; 45 were new detections in SiO masers. The selected IRAS sources were objects with dust temperatures of between 160 and 280K.
- ID:
- ivo://CDS.VizieR/J/PASJ/56/765
- Title:
- SiO maser survey of IRAS sources
- Short Name:
- J/PASJ/56/765
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We surveyed 401 color-selected IRAS sources in the galactic disk in the SiO J=1-0, v=1 and 2 maser lines at 43GHz, resulting in 254 (239 new) detections. The observed sources lie mostly in a strip of the inner galactic disk with boundaries -10{deg}<l<40{deg} and |b|<3{deg}. This survey provides radial velocities of inner-disk stars for which optical measurements cannot be made due to interstellar extinction.
